<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>递枕头</title>
</head>
<body>
  <script>
    function fn(n, time) {
      let i = time % (n - 1);
      let round = Math.floor(time / (n - 1));
      if (round % 2 === 1) {
        return n - i
      } else {
        return i + 1
      }
    }
    console.log(fn(4, 5))
  </script>
</body>
</html>